DNA BREAKAGE AND INACTIVATION RESULTING FROM HYDROXYLAMINE AND OR CIS-DIAMMINEDICHLOROPLATINUM(II) INTERACTIONS WITH PLASMID DNA
DNA BREAKAGE AND INACTIVATION RESULTING FROM HYDROXYLAMINE AND OR CIS-DIAMMINEDICHLOROPLATINUM(II) INTERACTIONS WITH PLASMID DNA
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DOI：
10.1016/0020-711x(93)90693-9
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发表时间：
1993-10-01
期刊：
影响因子：
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通讯作者：
BALAZOVA, E
中科院分区：
文献类型：
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作者：
RAUKO, P;NOVOTNY, L;BALAZOVA, E
1.将顺式顺铂和透明质酸诱导的DNA损伤程度量化为超螺旋pBR322 DNA的转化活性和构象完整性。在一次暴露于顺式顺铂(1hr/37度-C)后，观察到没有伴随可测量的变化或DNA构象的50%的质粒DNA的生物活性下降。HA以剂量依赖的方式诱导超螺旋DNA向其他拓扑形式的转化。用高灵敏度的电泳法测定单链和双链DNA断裂。与完整DNA相比，顺式顺铂暴露的DNA在HA浓度降低30倍时松弛。这种效应可能与顺式-DDP-DNA键上DNA结构的局部扭曲有关，这使得HA-DNA相互作用的高效成为可能。另一方面，尽管DNA诱导了突变，生物活性仍保持在50%的水平。这一发现支持这样的观点，即DNA断裂发生在DNA暴露于顺式DDP.7期间被修改的位置。DNA结构在与HA相互作用过程中的重要性可以在HA-DNA相互作用超螺旋DNA的热变性过程中看到。在此条件下，当HA.8浓度降低100倍时，DNA发生断裂。根据这些结果和以前发表的结果，我们得出结论，由顺式-DDP键引起的超螺旋DNA结构的局部扭曲和热变性引起的局部DNA解卷与高HA-DNA反应活性有关。
1. Occurrence of lesions induced in plasmid DNA by cis-DDP and by HA was quantified both as a transforming activity and as conformation integrity of supercoiled pBR322 DNA. Fifty per cent decrease of the biological activity of plasmid DNA, not accompanied by measurable change or DNA conformation, was observed after a single exposure of DNA to cis-DDP (I hr/37-degrees-C).2. HA induced conversion of supercoiled DNA to other topological forms in a dose-dependent manner.3. One- and two-strand DNA breaks were determined electrophoretically with high sensitivity. Cis-DDP exposed DNA relaxed at 30 times lower HA concentration compared to intact DNA.4. This effect may be connected with a local distortion of DNA structure at the cis-DDP-DNA bond, which makes possible high effectivity of HA-DNA interaction.5. On other hand, biological activity stayed at the 50% level despite breaks induced in DNA.6. This finding supports the idea that DNA breaks occur at the locations which were modified during the exposure of DNA to cis-DDP.7. The importance of the DNA structure during interaction with HA may be seen during HA-DNA interaction at heat-denaturation of supercoiled DNA. At this condition, the DNA breaks were induced at 100 times lower concentration of HA.8. We conclude, on the basis of these results and results published earlier, that local distortion of supercoiled DNA structure, which is caused by the cis-DDP bond, and the local DNA uncoiling caused by heat-denaturation are related to high HA-DNA reactivity.